1. Field of the Invention
The present invention relates to an ink jet ink, an ink cartridge using the ink jet ink, and an ink jet recording method.
2. Description of the Related Art
In recent years, concomitant with improvement in image quality and recording speed, an ink jet recording apparatus has been increasingly used in various business fields. As the performance required for an ink jet ink used in business fields, for example, ink reliability (such as ejection stability) and image fastness (such as scratch resistance and maker resistance) may be mentioned. In order to improve the performance described above, pigment inks containing various polyurethane polymers have been investigated (Japanese Patent No. 3897268, PCT Japanese Translation Patent Publication No. 2005-515289, and Japanese Patent Laid-Open Nos. 2006-022132 and 2010-195944). Japanese Patent No. 3897268 has disclosed that when an ink containing a pigment and an aqueous polyurethane polymer having specified acid value and number average molecular weight is used, the ejection stability and film properties (water resistance and abrasion resistance) are improved. PCT Japanese Translation Patent Publication No. 2005-515289 has disclosed an aqueous ink jet ink containing a polyurethane polymer dispersion having an acid group and a self-dispersing pigment. In addition, Japanese Patent Laid-Open Nos. 2006-022132 and 2010-195944 have each disclosed an ink containing a polyurethane polymer which uses an allophanate-modified polyisocyanate.